So, a long time ago, there were some people who lived in a place called Ukraine. They wanted to make their own country, separate from Ukraine. So, they called themselves the Donetsk-Krivoy Rog Soviet Republic.
This place was named after two cities, Donetsk and Krivoy Rog. They wanted to have their own government and their own rules.
But other people in Ukraine didn't like that. They wanted everyone to be part of Ukraine. So, they fought against the Donetsk-Krivoy Rog Soviet Republic and eventually they were not able to keep their own country anymore.
Today, Ukraine is one big country and Donetsk and Krivoy Rog are just regular cities in Ukraine.